Percent Energy from Fat Screener: Scoring Procedures
Recent Changes in Scoring
On July 19, 2004, an error was found in the data used to derive the scoring procedures. As a result,
the scoring algorithm was changed and the values for the gender-specific portion sizes and the regression coefficients
have been updated. You may download a new version of the SAS program used to calculate percent energy from fat from
the bottom of this page.
On October 12, 2003, the following changes were made to the calculations used to convert percent of energy from
fat from the screener data:
- Additional information about portion size was incorporated into the scoring algorithm.
- As before, a regression equation was used to estimate the individual's predicted percent energy from fat intake. However, because of the additional portion size information, a new gender-specific set of regression coefficients was estimated.
- Whereas the regression coefficients presented in the earlier program were estimated using only individuals 50 to 69 years old, the new regressions were estimated using adults 18 and over.
If you need the previous version of the SAS program, please send an e-mail to screeners@nih.gov.
Scoring Procedures
The following procedures were used to convert an individual's responses to an estimate of that individual's percent energy from fat:
- The frequency reported categorically on the questionnaire was converted to the number of times consumed
per day as shown below. In general, the midpoint
of the frequency range was used.
|
Frequency Response
|
Times Per Day
|
| Never |
0.0 |
| Less than once a month |
0.018 |
| 1-3 times per month |
0.066 |
| 1-2 times per week |
0.214 |
| 3-4 times per week |
0.499 |
| 5-6 times per week |
0.784 |
| 1 time per day |
1.0 |
| 2 or more times per day |
2.0 |
- The age- and gender-specific portion sizes for each food (shown below) were multiplied
by the frequency calculated in Step 1. These portion sizes were estimated from
CSFII 94-96.
| Median Serving Sizes (g) |
| Age |
Skim Milk |
Bacon |
Cold Cereal |
Fruit |
Mayo |
Dressing |
| Males |
| 18-27 |
366.666667 |
25.000000
|
74.666667
|
131.750000
|
13.750000
|
36.720000
|
| 28-37 |
250.000000
|
40.250000
|
61.500000
|
128.000000
|
13.750000
|
44.060000
|
| 38-47 |
250.000000
|
32.000000
|
57.500000
|
123.200000
|
13.750000
|
31.250000
|
| 48-57 |
245.000000
|
32.000000
|
56.000000
|
127.500000
|
13.750000
|
31.250000
|
| 58-67 |
214.375000
|
27.000000
|
46.000000
|
122.000000
|
9.150000
|
29.400000
|
| 68-77 |
198.937500
|
26.000000
|
39.000000
|
118.000000
|
13.750000
|
29.400000
|
| 78+ |
160.725000
|
24.000000
|
33.000000
|
114.250000
|
4.580000
|
29.380000
|
| Females |
| 18-27 |
245.000000
|
26.000000
|
50.000000
|
118.000000
|
13.750000
|
30.630000
|
| 28-37 |
245.000000
|
25.000000 |
49.500000
|
118.000000
|
6.880000
|
29.400000
|
| 38-47 |
244.800000
|
24.000000 |
44.000000 |
118.000000
|
9.170000
|
29.400000
|
| 48-57 |
229.690000
|
24.000000
|
43.500000
|
118.000000
|
9.183333
|
29.400000
|
| 58-67 |
196.000000
|
18.000000
|
33.000000
|
118.000000
|
6.110000
|
29.380000
|
| 68-77 |
183.750000
|
19.500000
|
33.000000 |
112.427143
|
10.310000
|
29.380000
|
| 78+ |
183.750000
|
16.000000
|
33.500000 |
109.000000
|
4.580000
|
22.030000
|
| Median Serving Sizes (g) |
| Age |
Eggs |
Fruit Juice |
Hot Dogs |
Cheese |
French Fries |
Margarine |
Rice |
| Males |
| 18-27 |
92.000000
|
373.200000
|
114.000000
|
33.360000
|
112.500000
|
9.540000
|
213.625000
|
| 28-37 |
92.000000
|
311.000000
|
85.500000
|
28.350000
|
114.000000
|
9.540000
|
195.000000
|
| 38-47 |
92.000000
|
249.000000
|
88.000000
|
28.350000
|
100.000000
|
9.460000
|
166.000000
|
| 48-57 |
92.000000
|
249.000000
|
114.000000
|
28.350000
|
100.000000
|
9.200000
|
165.000000
|
| 58-67 |
92.000000
|
248.000000
|
57.000000
|
28.350000
|
85.500000
|
7.883333
|
165.000000
|
| 68-77 |
80.000000
|
186.750000
|
57.000000
|
24.000000
|
85.500000
|
7.100000
|
158.000000
|
| 78+ |
80.000000
|
186.750000
|
57.000000
|
22.880000
|
97.000000
|
7.000000
|
158.000000
|
| Females |
| 18-27 |
80.000000
|
249.000000
|
57.000000
|
26.175000
|
79.500000
|
7.000000
|
158.000000
|
| 28-37 |
80.000000
|
248.800000
|
57.000000
|
21.000000
|
70.000000
|
6.290000 |
158.000000
|
| 38-47 |
69.000000
|
248.800000
|
57.000000
|
22.500000
|
70.000000
|
5.925000 |
158.000000
|
| 48-57 |
80.000000 |
217.875000
|
114.000000
|
22.063333
|
70.000000
|
7.095000 |
155.000000 |
| 58-67 |
68.000000
|
186.750000
|
57.000000 |
24.000000
|
66.000000
|
5.296667 |
122.250000
|
| 68-77 |
56.000000
|
186.600000
|
57.000000 |
21.000000
|
70.000000
|
5.320000 |
158.000000 |
| 78+ |
46.000000
|
186.750000 |
57.000000 |
25.800000
|
64.000000 |
4.865000 |
83.000000
|
- The proportion of the margarine and butter added to foods that was regular fat was estimated. First, the frequency of the margarine and butter added was calculated (totfat in the table below). This is the sum of the frequencies for the three questions in question 1 for margarine and butter added to food (on bread, rolls, pancakes; vegetables including potatoes; and rice or pasta).
totfat = sum(marg on bread, marg on veg, marg on rice)
Then the information in the instrument's second question, "how often was reduced-fat margarine used?" was applied, using the following equivalents:
|
Response to Question 2
|
Value of Regfat
|
| Didn't use or almost never |
totfat |
| About 1/4 of the time |
totfat*.75 |
| About 1/2 of the time |
totfat*.50 |
| About 3/4 of the time |
totfat*.25 |
| Almost always or always |
0 |
- The individual's percent energy from fat was estimated by applying regression coefficients to each food item. The following equation was used to estimate percent energy from fat (the dependent variable), for each gender:
estpcalfat = intercept + (b1*cereal) + (b2*skim milk)
+ (b3*eggs) + (b4*bacon) + (b5*citrusjuice) + (b6*fruit) + (b7*hotdogs)
+ (b8*cheese) + (b9*friedpot) + (b10*mayo) + (b11*salad dressing)
+ (b12*rice) + (b13*reg.fat)
The values used for each regression coefficient are in the following table:
Estimated Regression Coefficients for Foods as
Predictors of
Percent Energy from Fat, by Gender |
| Parameter |
Male |
Female |
| Intercept (b0) |
30.795765
|
29.865870 |
| Cold Cereals (b1) |
-0.022086
|
-0.045171
|
| Skim Milk (b2) |
-0.009666
|
-0.010393
|
| Eggs (b3) |
0.026997
|
0.036787
|
| Bacon or Sausage (b4) |
0.109569
|
0.198808
|
| 100% Fruit Juice (b5) |
-0.004946
|
-0.010141
|
| Fruit (b6) |
-0.009346
|
-0.012103
|
| Hot Dogs (b7) |
0.040118
|
0.106686
|
| Cheese (b8) |
0.069945
|
0.103239
|
| Fried Potatoes (b9) |
0.024262
|
0.040374
|
| Regular Mayonnaise (b10) |
0.145026
|
0.287044
|
| Regular Salad Dressing (b11) |
0.114649
|
0.182758
|
| Rice (b12) |
-0.017017
|
-0.014224
|
| Margarine (b13) |
0.167937
|
0.326702
|
Note that Question 3 was not used in this scoring. This last question by itself is correlated with percent energy from fat, but it is unnecessary if the other questions are used to more precisely estimate the individual's percent energy from fat.
SAS program to calculate Percent Energy from Fat using the Short Screener
|
